Electric burglar-alarm



(No Model.) j 2 Sheets-Sheet o. P. A. STURTS.

ELECTRIC B'URGLAR ALARM.

IPatented Feb. 28.1893.

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2 Sheets-Sheet 2.

(No Model.)

C. I'. A. STURTS.

-ELEGTRIG BURGLAR ALARM.

No. 492,478. Patented Feb. 28, 1893.

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businessi1 hours, doors, windows, transoms, &c.,

UNITED STATES PATENT OFFICE.

CHARLES A. sTURTsoF SAN FRANCISCO,v cAiJFoRivIA.`

ELEcrRlC Bu RcLAR-ALARM.

SPECFICATION forming part of Letters Patent No. 492,4?8, dated February 28, 1893.

Application iiled September 30, 1891. Serial No. 407,257. (No model.)

l.To aZZ whom it may concern.- x

Be it known that I, CHARLES F. A. STURTS, a citizen of the United States, residing at San Francisco, in the county of San Francisco and State of- California, have invented certain new and useful Improvements inElectric Burglar- Alarms; and I do hereby declare that the fol- Vlowing is a full, clear, and exact description thereof.

This invention relates toelectric burglar alarms adapted to the protection of buildings, suchas stores and ware-houses, and particularly in the absence of their proprietors. The object of my invention is to provide an exterior alarm mechanism located at some point on the outside vof the building, and

adapted to notify police or passers-bythat an.

` attempt is being made to gain ingress into the building. The alarm is located in an independent bell circuit, which when once closed will cause it to sound continuously until`the circuit is positively broken by direct mechanical means. This bell circuit is closed by means of another circuit extending to doors, windows, transoms, and other points of possible admittance, and also lo the main lock of the entrance door which is the con- 'trolling point. This circuitis normally open -at each door, window, and transom, and is also open at the door lock, excepting when the latter is locked. In the latter case, the circuit is normally closed at the lock, but re- 'mains open at each door, window and transom. An attempt to open any oneof these, will close the circuit there, throw in the bell circuit, and sound the alarm continuously;

and no cutting of wires, or displacement of parts in, the outside circuit can thereafter affeet the alarm. From this it will be seen that While the entrance door is unlocked during may be operated as usual,without possibility of completing the circuit and sounding the alarm.

'lhe above is a general description of the alarm, but for a full comprehension thereof, reference must be made to the following detailed explanation and to the accompanying drawings.

In the drawings-Figure l, is a diagram to indicate the location of` a door, Window, and transom, the bell striking mechanism 1n open circuit, the battery and electrical connections to such door, window and transom.. Fig. 2, is a detail elevation of the bell striking mechanism in closed circuit, aswhen in operation. Fig.,3, is a vertical section, showing the-upper lefthand corner of the door in Fig. 1. Fig. 4, is a section on line :1;00 of Fig. 3. Fig. 5, is a longitudinal section to illustrate electrical connections tothe door lock. Fig. 6, is a horizontal section of the same. Fig. 7, is a sectional View of one of the insulatingplates for the door lock. Fig. 8, represents in perspective, the lspring contacts for closing the circuit when the door is locked. Fig. 9, is a detail perspective of the bell striker and the hook or trigger which forms the closerfor the V.bell circuitn- The diagram, Fig. l, does not correctly represent the relative proportions or location of the parts of my apparatus as they would be used in practice. The door A, Window B, and transom C, are merely supposed to form parts Vof a building to be protected, and their relative positions are not and need not be, accurately shown.

The door, window and transom are taken to illustrate three common methods of obtaining unauthorized ingress to `a building; but any lnumber of dloors, windows and transoms may be connected in the manner to be hereinafter described, all prof tected by my alarm apparatusl The alarm mechanism illustrated in different positions in Figs. land 2, is supposed to be inclosed in a box or case, situated at,

some inaccessible point upon the exterior of the building, where its operation will give notice to the police or passers-by that an attempt at entrance is being made. D, will therefore represent the back plate of such a box, to which the bcll mechanism is secured'.

The battery E, is concealed at any'T point, as

in a cellar or basement, or if preferred, it may be carried by and inclosed within the box which contains the bell mechanism.

One of the battery Wires l, runs to the binding post 2, in thebox D, the latter being electrically connected to the electro magnet F, the armature of which carries the bell striker 3, and thence the Wire 1, runs ,to the binding with the armature. The other battery wire 4, extends to a binding post 5, which has a IOO 4post l, which has the usual screw for contact I contact point 6.l Y Another binding post 7, havy-ng -a contactL point 8, is electrically connectedfto the armature by the wires 9 and l10,.

and' post 11. The connections thusfar described indicate an opengbell circuit. e

G, represents a trigger pivoted at its upper endV and having a spring 12, which tends .to .throw it into contact with the points 6 and 8. Itis however' normally kept out4 of contact and the bell circuit kept open,by a pin'l3 on the armature, over which its hooked end is caught, and by which it vis helduntil the armature is attracted. It will ,then be re-A leased, and -will make contact at both 6 and 8, closing the bell'circuit and permitting `the bell striker te vibrate continuously in the usual manner of an electric bell. The course 'of the 'closed circuit is, battery, Wire, 1, magnet,'and through the connecting wire to the 'binding post l, thence through thearmature to the wires 9 and 10,-trigger G, wire 4, to theV battery.v The bell will ring continuously until i the circuit is broken at contact point 8. This is accomplished bya rod, wire or cord 14, inclosed within a tube 15, and connected, t a bell crank 16. When this cord is pulled, the bell crank will push the trigger G, forward by striking its "projecting end L17, breaking the circuit at S,- and causing the trigger to re.-

",-which controlsfthe trigger G, I prefer to con'-y engage'withfthe armature. The parts are' shown, in Fig. 2, in closed circuit, with the bellringing.,\ 1 l.

:'To avoid vtampering with the cord or Wire nect such cord or wire` to a pivoted lever18, carried in a case v 19, resembling a lock case,

'i and accessible only by a key`or other instruy ment inserted from the'ontsfide, and capable.

v of turning the center pin 20. Suchlvpin' has and thus pulls the .cord or wire llt. The purpose of" inclosig the 00rd 0r rod a projection' 21,'which strikes the lever.l 18,

14,. in the tube 15, isof vcourse to prevent ace having no positive connection to trigger G, a l person attempting to' stop ythe Valarm Vmight cess toitby unauthorized persons; concealed and protected as `it is, and the bell crank 16 pnlldown'thje whole tube, bell crankQ-dcase I Q20, withut ,elecnvfor unless he could Vpull sce o the circuit. The key whichcontrols'the levezv ltl1e"'u`fire litindependently heycfould not open y 18, would ofcourse only be intrnsted-to police,

or watchmemor other responsible parties.

I'haye thus far described the constructioni -and arrangementof,anaoalarin mechanism in..

' shown inthe drawings.

vtasti-sv :"o't'ner' pointsof possible ingress. There is thus formed, a normallyopen circuit, which, when the door is' unlocked is-broken atV the door, at each Window, and kat eachtransom.

When the door is locked, the circuit is'closed vat the lock, but'remains open'at the othercontactsf New if a window-,for cumpla-should be raised, the circuit will also be closed at such window, which will complete itto the. battery and magnet, and the alarmwlll sound continuously as before explained. I now describe the details of this mechanism, referring to Figs. 1, 3, 4, 5, 6, 7, and 8. y The main door-lock H, may be 'of any de-A fsired construction and its mechanism, with the exception of its sliding. bolt 22, is not p It is inclosed within ametallic case 23, (Fig. 6,) and; is insulated therefrom so that the lock itself is neverin .Se l

circuit, In one end of the case 23 (Fig.l 5),

are two normally separated metal springs 25,

*2.6, kept apartvby the pressure of the lockbolt 22, but permitted, 'asshown in dottedjline,;

to make a contact when the pressure-of the boltv lis removed by locking the "door, These springs are separately illustrated io"`Fg 8 A wire X, extends from the bindng'pt 1l, which/ as before stated, is in electrical connection with the armature, is connected tothe door hinge, (a convenient wa'ylof avoiding oornplication :at that point) and then contini', 1' ues and is connected to thespringscontact 25 f at the lock. Anothenwire 28,'runnli fromv the contact 26, is connected tothe battery 'wire Yg. 4New `if this circuit, which includes the battery and magnet, and which is Vnormally open is completely closed, by any one l of the circuit closers 30,131, 33,;34n`o`r 37, 38, the alarm will ring continuously; andBQ'my roo I purpose is to-haveth'e circuit closed at the Y lock and open at' other points, such for illustration 4as the door, windowfand; transom shown. `Taking the wiido'wB, andreferring to Fig. 1, it will be'seen that 'the wir@ 28 passes first to the upper doorfhin '45p-and' 4 is then connected to onefof'two. 'contat .rings 30,` 31,'sit'atedata point in thevwiniowfeas-zf ing, and kept out of contact', whex'r't-he Window vis' closed by a stud32 ontheisash Freni .the contact 31' the wire`28 rnhsgtozthe wire Ye` NOW the circuit,'jalithoughrcloeed at Vthe lock by contacts 25, 26;;1 .n'mtmapy jj at the window and will remaiuo'peiruntiie tritfzal connection is riielie through 'contacts 3Q and 31.

batteri' ,the lstud 32 past the spring 30, the circuitwill i be closed at that point also, the battery thrown in, the magnet energized and the alarm sound-'- ed. If the burglar should be sufiicientlyin tac'ts 33, 34, one connected by a wire 35 to thev l13o A Similarly the transom C is provided with con-fl battery Wire Y, and the other by a Wire 29, to?

the wire 28. These contacts are held apar-t:

4by a stud 36, when the transom is closed. Should it be opened however, the spring 34 is released and a contact made. The course of the current is now, magnet, wire X, con- 5 tacts 25, 26, at the lock, wire 28, wire 29, contacts 34, 33, wire 35, wire Y, battery, and the alarm will be sounded asbefore. The window and transom are now provided with safeguards. The door A, must however, be supro plied with a similar device, which in the diagram, is shown in its left hand upper corner.

There are special features of construction here which I have separately illustrated, but

at present I refer only to Fig. 1, as affording I5 a clear illustration ofthe course of the circuit without reference to details. In the cas- -ing of the door are contact springs 37, 38, one

connected to the battery wire Y, by a wire 138, the other to the wire 28, bya wire 39. A

zo projection on the door keeps them apart until the door is opened, when they are released and close the circuit, the course of which is now, magnet, wire X, lock, wire 28,

wire 39, contacts 38, 37, wire 138, wire Y, bat-` 2 5 tery, the alarm sounding continuously.

I now describe means provided for sounding the alarm in case any attempt is made to tamper with the lock itself; and I refer especially` to Figs. 1, 5, and 6. As before mentioned, the lock is inclosed in a metal case and insulated therefrom, as shown by heavy black lines in Fig. 6. Toward the outside of the door, but within the metal casing, is a thin metal plate 42, insulated from the case 23 by a thin perforated sheet 24 of some insulating material, (shown separately in Fig. 7.) The contact point 25, (and consequently the wire X and magnet,) is connected to the plate 42 by a wire 43; while the case 23, is connected tobattery wire Y by a wire 44. The insulating strip will ordinarily keep the plate 42 and case 23, out of contact; 4but if a punch or other instrument be inserted so as to strike the case 23, thelatter will be forced inwardly and 45 will make contact with the plate 42 through one or more of the perforations in the strip 24. This will close the circuit and sound the 1 alarm in the manner before described. I

have explained these four methods of protecting diierent vulnerable points, in order to clearly illustrate the fact that by a very simple arrangement of circuits, any number of such points may be placed in circuit. The arrangement of the wires and other mechanism at allof such points is substantially` the same, the only changes being those required by the different locations of and constructions at those points.' Figs. 3 and 4 therefore, which are sectional views at the left hand upper corner ofthe door,will be understood to show substantially the details of the mechanism'employed at windows and transoms also.l I prefer to protect my wires by tubes, as 45. One of such tubes may also be utilized as indicated in Figs. Sand 5 (which may be read together), to connect the wire 44 to the wire Y.V Fig. 3 Valso shows passages formed in the door'and its casing'to receive the wires, and indicates the connection of the wire 28 to the upper door hinge 46, the hinge lthereby becoming a part ot the conductor.

The operation of my burglar alarm has been so fully set forth in connection with the description, that no special explanation will now be required. Attention is however called to one point which shows a particular advantage of my device aside from its use as a protection. It will also operate to give a warning against leaving the building unprotected. If on locking the main door at night, a window should have vbeen left open, the circuit will have been closed at that window; 'and the operation of vlocking the door will close the circuit completely, and sound the alarm, thus notifying the person leaving, that some eX- posed point has been left unfastened. The principal advantage of my alarm system, however, lies of course in the fact, that after the bell circuit has been established the alarm will sound continuously; and no eort of any unauthorized person who has caused it to sound, will avail to stop it even though such elfort should destroy the whole external circuit.

What I claim is- 1. A burglar alarm consisting of an alarm in a bell circuit, and an external circuit includin g a door lock and one or more places of admissionfsuch asa window, the circuitbeing normally open at such window, and closed at such lock when the door is locked, whereby the closing of the circuit at the window will throw in the bell circuitand sound a continuous alarm, substantially as set forth.

2. An electrical burglar alarm consisting ot' an alarm in a normally open bell circuit, an external circuit which includes the lock of a door, at which point it is closed by the locking of the door, such circuit also including one or more windows or like means of ingress, and circuit closers at such' window, normally out of contactbut adapted to make contact when the window is opened, all constructed and arranged so that, when the dooris locked, the opening of the window will complete the external circuit, throw in the independent bell circuit, and `cause a continuous alarm, substantially as set forth.

`3. In an electrical burglar alarm the combination of a magnet and battery, an armature carrying a bell striker, an electrical circuit including said parts,a pivoted trigger normally in engagement with'the armature, and an external open circuitincluding one or more windows or similar means of entrance, all constructed and arranged so that the closing of the external circuit will cause the release of said trigger, the closing' of the bell circuit, and the sounding of a contin tially as set forth. p

4. The combination of the bell operated by an electro magnet in a bell circuit, the trigger G normally in engagement with the armature of' the magnet, the contact points 6 IOO IIO

nous alarm, substanand` 8, die-bell crank 16,- rod 14 tube 15, case said plate 42 and -said metalcasmsuzbstan- '19,and lever 18 in said oase adapted to be opially as and for the purposes eet forth.

` erated from the '.outsidebyA a key, substam Iu `testimony whereof I haye ailxed my sigtially 'asand for` 'the purposes set forth. y nature, in presence of two witnesses, thi$l7th 5 5. IIn a burglar alanmand in combination,I day of September, 1891. i.

a bel! circuit includinga magnet a battery 1 v CHARLES FICA STURS v. I

and a bell, erdoor loekfinclosed in a metal case,a plate 42'usuiatd from said case bya Witnesses:

' perforated strip,` and 'electrical connections H. J. LANG, v Y 1o fr'oneaid magnet and battery respectively to ,L W. SEELY.l 

